Adhesive fastener elements are employed for a variety of purposes, such as in automotive technology, flooring technology and clothing of all kinds, and for special applications in mechanical engineering. Adhesive fastener elements have proved themselves to be reliable detachable connection and fastening elements in these fields. When such adhesive fastener elements are used for aircraft or motor vehicle passenger seats, they fasten seat covers to foamed parts. Some adhesive fastener elements are foamed into the foam upholstery material during production of the respective seat, while another, mating adhesive fastener element with the corresponding interlocking elements is fastened to the cover upholstery material, in particular is sewn on. For producing the foam body element, the adhesive fastener elements are introduced into so-called seating pipes of a foam injection mold. By introduction of foam material into the free cross-sections of the foam injection mold, preferably one of polyurethane (PU) foam, the adhesive fastener elements are fastened on the foam body elements in the foam injection process. The pipes employed normally project above the other walls of the foam injection mold and thus later form groove-like recesses in the foam body element that is then engaged in the upholstery cover material with the other corresponding adhesive fastener element. In this way, geometric seam and shape patterns may be produced on a particular seat.
DE-A-199 56 011 discloses an adhesive fastener element for this purpose in the seating area. The adhesive fastener element has a support strip and interlocking elements mounted on the support strip. The support strip has at least one reinforcing element resistant to bending and extending preferably along the support strip in the form of a bending wire. Application of the solution disclosed results in better embedding properties in foam molds for adhesive fastener elements. Because of the flexural strength of the reinforcing element, once adhesive fastener elements have been introduced into the respective foam injection mold, they remain in their position. The disclosed cover strip is applied in one layer to be flush with the upper side of the foam injection mold. During the foam injection process involving polyurethane foam (PU), the foam may raise the cover strip above the side edges of the foam injection mold and reach the interior of the duct-like injection mold in which the support strip with the bending wire and the interlocking elements is seated. However, penetration of the intermediate areas of the interlocking elements by the foam weakens the fastening capability of these elements. They may then not be effective when engaged with corresponding closing elements of the other component. The penetration reduces the adherence of the disclosed adhesive fastener elements.
In order to offset this disadvantage, DE-A-100 39 940 proposed, for a generic adhesive fastener element, a cover strip wider than the support strip. The two free side edge areas of the cover strip are each folded back themselves in the direction of the support strip along a fold line extending in the longitudinal direction. The end edges of the free side edge areas of the cover strip then face the longitudinal edges of the support strip. As a result, the cover strip has on both sides a sealing lip always extending along the area having the interlocking elements and being adjacent to the wall elements of the foam injection mold enclosing the molding depression in which the interlocking elements are received during the foaming process. The foam material introduced into the foam injection mold causes this sealing lip to be pressed against the facing wall elements of the mold. As a result of the certain amount of flexibility in the area of the fold line, the sealing lip rests against the wall areas forming the sealing surface so that the improvement desired in the sealing action as foam barrier is achieved. To impart a certain amount of flexural resistance to the adhesive fastener element, something perceptibly improving handling during introduction into the foam injection mold, this disclosed solution also has a flexurally-resistant element in the form of a bending wire.
Unintentional penetration of foam material in the direction of the interlocking elements may occur even with these disclosed solutions despite this sealing lip configuration. It has been found in particular that the previously disclosed sealing solution encounters its limits where the foam injection mold has no molding depression (cost-intensive in production) for reception of the interlocking elements of the adhesive fastener element.
Since both of the previously disclosed solutions have recesses in the foam injection pipe to receive the interlocking elements, problems also arise in surface cleaning of the mold, since fouling matter may unintentionally settle there.